Outpatient administration of radioactive iodine after total thyroidectomy for pediatric thyroid cancer: A report of three cases

Radioactive iodine is used as an anti-cancer reagent for papillary and follicular thyroid carcinomas. Patients that are administered a large dose of radioactive iodine are required to stay alone in an isolated room for several days. Some young children with thyroid carcinoma who cannot take care of themselves are not able to undergo this therapy. We tried outpatient administration of 131I for these patients. In Japan, administration for outpatients is restricted to 500 MBq (13.5 mCi). We administrated 13 mCi 131I to three patients suffering from pediatric thyroid carcinomas. One patient with recurrent follicular carcinoma in the neck showed complete loss of the thyroid bed and an undetectable level of serum thyroglobulin 7 months after the first administration of 131I, and no further recurrence was observed after 5 years. Another patient with multiple lung metastases showed weakened uptake of 131I in the lung and an evident decrease in serum thyroglobulin after administration. However, the last patient with lung metastases with a low 131I uptake showed no evident change in either 131I uptake in the lung nor the serum thyroglobulin level. Administration of 13 mCi 131I was effective in two of three patients. Thus, it is worth considering this therapy as a practical option for pediatric thyroid carcinoma in the countries in which outpatient administration of a large dose of 131I is restricted.